When Robert Griffin III runs the ball he has an advantage that a running back carrying the ball does not. He has an extra blocker.
Will Montgomery explained that the QB keepers make the defense play more honestly.
“Usually you hand it to the running back and the defense has an extra guy in the box,” he said. “But if the defense brings down the eighth defender and the quarterback’s running the ball you have that extra blocker. The tables are a little more even than they usually are.”
The extra blocker that Montgomery is referring to is the running back. If the quarterback hands the ball off he usually continues to move away from the action. But when the QB carries the ball, the running back serves as a blocker. That gives the offense one more blocker than it usually has.
In theory, a quarterback keeper turns a matchup that has nine offensive players (the 11 on the field minus the quarterback and the runner) trying to block 11 defenders into a more even 10-on-11 matchup.
Add that to the wheels that RG3 has displayed and you have the potential for some big plays. Griffin and the Redskins have to pick their spots, of course, since you don’t want to have your quarterback carrying the ball 15+ times per game but it is still a weapon that they would be foolish to leave in their holster.